The treatment of cardiac dysrhythmias has changed significantly since the introduction of the technique for catheter ablation by means of high-frequency current. In this technique an ablation catheter is introduced under x-ray monitoring into one of the ventricles, via veins or arteries, and obliterates the tissue causing the cardiac dysrhythmias by means of high-frequency current. For catheter ablation to be completed successfully, it is necessary for the cause of the cardiac dysrhythmia to be precisely localized in the ventricle. This localization is effected by means of an electrophysiological investigation, in which electrical potential is recorded with spatial resolution by means of a mapping catheter introduced into the ventricle. This electrophysiological investigation, known as electroanatomical mapping, thus produces 3D mapping data that can be displayed on a monitor. The mapping function and the ablation function are therefore often combined in a single catheter, so that the mapping catheter may also function simultaneously as an ablation catheter.
A known electroanatomical 3D mapping method, as may be implemented—for example—with the CARTO system by the company Biosense Webster Inc., USA, or the ENSITE 3000 system by the company Endocardial Solutions Inc., St. Paul, USA, is based on electromagnetic principles. Three different magnetic alternating fields with low intensity are set up under the examination table. By means of electromagnetic sensors integrated in the tip of the mapping catheter it is possible to measure the voltage changes within the magnetic field that are induced by catheter movements, and—with the help of mathematical algorithms—to calculate the position of the mapping catheter at any point in time. By point-by-point mapping of the endocardial contour of a ventricle using the mapping catheter, with simultaneous recording of electrical signals, an electroanatomical, three-dimensional map is produced in which the electrical signals are displayed with color-coding.
In addition to electroanatomical 3D mapping systems of this type, there are also intracardial localization systems such as—for example—the Localisa system by the company Medtronic, Minneapolis, USA, which use localization of the catheter and design of a 3D image of the examined ventricle. The data obtained using a localization system of this type is also referred to in the patent application as 3D mapping data, since it delivers a comparable 3D image of the examination area.